Deep Chlorophyll Maximum in Western Equatorial Atlantic - How does it Interact with Islands Slopes and Seamounts?

Abstract

This paper investigates the dynamics of the deep chlorophyll maximu m layer (DCM L) along the Fernando de Noronha Ridge in the oligotrophic western equatorial Atlantic off northeast Brazil. M ixing processes between water masses above and below the thermocline may occur in a scale of tens of meters around the 24.5 to 25.5 isopycnals, where photoau-totrophs are concentrate at the bottom of the euphotic zone. The primary production at the DCM L can provide 210 (±170) metric tons of Carbon per day to the benthic community at the Rocas atoll. The behavior of isopycnals in deeper and strongly stratified waters suggest that internal waves may imp rove primary production, by lift ing the deeper and nutrient-rich South Atlantic Central Water upwards and carrying the autotrophs to brighter depths.